This is the last part of the Legacy System’s series. The first two parts were discussed about Definition of Legacy System (Part 1) and Characteristic of Legacy System (Part 2). Now, we are looking on what kind of problems potentially caused by Legacy System. Let’s jump in…The most common reasons why the legacy systems are still there is because the legacy systems play critical role in business process as a backbone of information flow (Bisbal et al., 1999). As consequences, to keep those legacy systems running in their organization, CIO’s and IT executives are, at least now facing some difficulties caused by legacy systems such as:

High operational cost: By keeping legacy systems alive, the cost for maintaining, operating and monitoring will be more expensive.

Difficulty of maintain: Due to scarcity of experts and up-to-date documentation, the maintenance of legacy systems is difficult. Legacy system mostly was developed with early programming language (such as ASM, COBOL or JCL etc.,), and the development framework or environment of legacy software has been outdated.

Unsupported hardware and software and inability to be updated: Because out-of-date technology, it is hard to update the legacy systems. Legacy systems which were built many decades ago are becoming slower now because they are running on obsolete hardware (Paradauskas & Laurikaitis, 2006). These old legacy systems are often not supported by their suppliers or vendors anymore.

Hard to find qualified experts: It is predicted that in the future it will be difficult to regeneration skilled people who are experienced with legacy systems. The reason is because the existing experts are getting old or nearly to their retirement day and not many young people are interested in the old technology.

Complex in integration issues because of poor and rigid architecture system: The architecture of legacy system is mainly stovepipe architecture and haphazardly design. Thus, legacy systems is a monolithic (e.g. without clear distinction between user interface, application logic and business model) (Nowakowski, et al., 2012). With this characteristic, a legacy system has difficulty to integrate with other systems because of non-extensibility, incompatibility, and less-openness of the underlying hardware and software of these legacy systems (Bisbal et al., 1999).

Rigid to changing business requirement: Legacy systems are well known for their resistance towards modification and evolution. It makes the process of updating the new functionality slower and leads to higher time-to-market.

Not well documented: The common problem of legacy systems is that systems often lack up-to-date documentation and knowledge about the system is often unsatisfactory because of the retirement of the expert (van Geet, Ebraert, & Demeyer, 2010). So lack of knowledge written down on paper.